1. Field of the Invention
The present invention relates to an image recording apparatus and, more particularly, to an image recording apparatus to perform image recording by an ink jet system.
2. Description of the Related Art
As an image recording method for record images easily and at low cost, many types of image recording apparatuses using an ink jet system have been used. The image recording apparatus using ink jet system is such that ink is jetted from nozzles of a recording head as fine ink droplets toward a recording medium such as a paper or the like with, for example, a piezoelectric element such as a piezo element or a heater, and the recording head is moved over the recording medium while making the ink penetrate into or fix onto the recording medium to thereby record images on the recording medium.
Recently, as a method for forming images even onto a recording medium with poor ink absorptivity such as resin film, an image recording apparatus which uses ultraviolet curable ink has been known (refer to for example, JP-Tokukai-2001-310454A), in which ultraviolet curable ink comprising photo initiator with a predetermined sensitivity to ultraviolet rays is used, and the ink placed on the recording medium is cured by irradiation with ultraviolet rays to be fixed thereto. This method allows images to be easily recorded even onto transparent or nontransparent packing material.
However, in the image recording apparatus of the ink jet system, the ink jetted from the nozzles of the recording head is turned into spray to disperse, causing the ink to adhere to a portion outside the recording medium. For example, in the case that the ink dispersed is adhered to a portion near the nozzles, the ink would stack in the nozzle to cause clogging, thereby raising a problem for image recording.
The ink dispersed from the nozzles may adhere to a platen as well as the portion near the nozzles. Specially, in the case of using cationic polymerizable ultraviolet curable ink or the like whose main component is a monomer, the monomer has a property to make resin such as plastic melt. Therefore, a platen made of plastic is melted at a portion to which the ink is attached, causing irregularity on the surface thereof, thereby raising a problem that the recording medium may not be carried smoothly for image recording. A platen made of metal such as aluminum would not be damaged by the melt on the surface, however, because the ultraviolet ray curable ink is cured by irradiation with light, the ink adhered to the platen may be cured, thereby causing irregularity on the surface of the platen. Therefore, the same problem is raised so that the recording medium is inhibited from being carried.
The ink which turned into spray may adhere to a portion of a maintenance unit. For example, when the ink adheres to a suction cap provided on the maintenance unit, the ink is cured on the suction cap by irradiation with light. It would inhibit a contact between the nozzle face of the recording head and the suction cap for maintenance of the recording head, resulting in failing to perform an appropriate maintenance of the nozzles.
Accordingly, for performing stable and high definition image recording, the ink which turned into spray to be dispersed on each part of the nozzles of the recording head, the platen, and the maintenance unit should be appropriately removed to keep an appropriate condition for image recording.
For removing the ink adhered to a portion around the nozzles of the recording head, there is known to provide a space for purging ink residue within a recording head movable region. The maintenance is performed by purging ink residue to the provided space every time a certain amount of image recording is completed (for example, see, JP-2675887B).
However, providing a specific space for purging ink residue would cause the need to make the apparatus be large by the size of the space. Since the ink residue purged into the space needs to be fed to a waste ink tank, a mechanism for suctioning and feeding the ink jetted to the space is required. However, providing such a mechanism would make the apparatus be large and complicated, thereby raising a problem to increase the cost for manufacturing the apparatus.
Specially, use of ink with high viscosity such as cationic polymerizable ultraviolet curable ink for performing image recording would cause a problem that the ink is difficult to be fed to the waste ink tank. For example, the ink with high viscosity easily adheres to the waste ink path when feeding the ink, and further the ink suctioned would clog in the waste ink path, thereby failing to perform the suction operation. Therefore, for smoothly feeding ink to the waste ink tank, a special member needs to be provided for raising a suction pressure to suction ink residue purged, resulting in a problem that the apparatus becomes large and the cost for manufacturing the apparatus is increased.
Appropriate maintenance operations for portions of the platen or the suction cap are also required, however, in the related art, the maintenance operations have not been performed for these portions. Thus, the apparatus could not be kept in a proper condition by appropriately removing ink which turned into spray for performing image recording, thereby raising a problem that it is difficult to stably perform high definition image recording.